WHICH IS BETTER: PUSH OR PULL?

This depends on the application. If your backup server is secure,
definitely use the pull method. In that case, the only potentially useful
part of rlbackup to you is powershift.cc.

Rlbackup uses the push method. The push method is more suitable for
symmetric situations, where both machines are production servers and
equally likely to be hacked. In that event, hackers will have access to the
backup, but not original, copies of data on other live production
machines. Providing this security is the purpose of rsyncsh: if a backup
server is hacked, you definitely don't want to provide the hacker with
root access to its clients!